It has previously been attempted to manually withdraw and rotate a signal-producing-sensor probe or fiberscope through a zone of a tube which is desired to be inspected and to visually note the probe of fiberscope position while recording the signal or view from such inspection for analysis. An automatic indexer assembly as disclosed in U.S. patent application Ser. No. 916,349, now U.S. Pat. No. 4,770,053 but filed Oct. 7, 1986 by Michael Luedke, and assigned to the same assignee as the instant application, provided a means remote from the tubesheet and tube opening to eliminate or diminish intermittent variables which may distort the signal to be recorded. Motion and control came through a long probe tail torsionally driven by telescopically assembled shafts, to which it was clamped. The indexer includes a slip ring and a fluid swivel.
In the case where it has been desirable to perform fiberoptic inspection of tubes, tube support plates and sludge, typically, during used tube removal, the current practice is inefficient and inconvenient. It includes having an individual position and hold the fiberscope within the radiation contaminated steam generator.
Positioning and manipulation of the fiberscope is directed by an individual at a monitor in an uncontaminated area. The director is in head set communication with the individual in the steam generator head. The fiberscope is focused by an individual in a containment tent.
Tube bow or dent measurements are performed by the insertion of a backlight and/or target from the opposite tube end. The target is viewed with a forward facing fiberscope and the tube bow is measured by the displacement of the target centerline from the fiberscope centerline. Bow measurement requires coordinated operation between the fiberscope and backlight and the maintenance of relative distances within the tube.
Accordingly, there is a need in the art for a remote controlled manipulator capable of inserting or retracting a fiberscope, backlight or other tube visual inspection device along the length of a tube. The manipulator should be capable of rotating the device 360.degree. at any location along the length of the tube.
The manipulator should be capable of positioning fiberscopes such as an Olympus Fiberscope (IF-8D3-30) (8 mm), an Olympus Fiberscope (IF-6D2-30) (6 mm), a Welch-Allyn Video Probe (1/4 inch), or a backlight.
The manipulator must position several sizes (OD) of visual inspection devices. Also with advances in inspection probes, probes of other sizes may be positioned in the future. This requires drive means which are independent of a particular probe size.
In addition, it is clear there is a need in the art for a more compact, easier to handle and still accurate means of manipulation of a probe, including a fiberscope, by motors and drive means on a base fixedly mounted adjacent the lower side of a steam generator tube sheet instead of manually or by motors outside of the steam generator, as in the case of the previously described automatic indexer assembly.